On certain packing lines for producing packets of cigarettes, each packet is marked with a code indicating, for example, the date of manufacture and/or the plant at which the packet was produced.
Packets of cigarettes are normally in the form of a rectangular parallelepipedon comprising a pair of opposite major lateral surfaces, a pair of opposite minor lateral surfaces, a bottom surface, and an opposite top surface; and each packet is normally marked on a portion of the bottom surface or a portion of one of the minor lateral surfaces.